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library/timeout.yap

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+/*************************************************************************
+*									 *
+*	 YAP Prolog 							 *
+*									 *
+*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
+*									 *
+* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
+*									 *
+**************************************************************************
+*									 *
+* File:		timeout.yap						 *
+* Last rev:	5/12/99							 *
+* mods:									 *
+* comments:	Goal within timeout					 *
+*									 *
+*************************************************************************/
+
+:- module(timeout, [
+	time_out/3
+    ]).
+
+:- meta_predicate time_out(:,+,-).
+
+%
+% not the nicest program I've ever seen.
+%
+time_out(Goal, Time, Result) :-
+	T is Time//1000,
+	% enable alarm
+	alarm(T,throw(time_out),_),
+	% launch goal and wait for signal
+	( catch(Goal, time_out, Result = time_out)
+        % make sure to disable alarm
+          ->
+	    alarm(0,_,_)
+	  ;
+	    alarm(0,_,_),
+	    fail
+	),
+	% just couldn't resist...
+	(Result = success -> true ; true).
+